Some restaurants may be equipped with one or more self-serving dispensers, for example, ketchup and mustard dispensaries at fast food restaurants, and creamer and sugar dispensaries at coffee shops. Commonly, these dispensers are not closely monitored by the staff at the restaurant, and it may be easy for someone with ill intent to intentionally poison the contents of the dispensers. For example, someone may poison the contents of the creamer dispensers at a coffee shop. These restaurants have the added responsibility of ensuring the safety of the contents of the dispensers used by its patrons.